they are reasonable. My reasoning for going with them, was cost. I could replace them 2-3 times before the cost of a set of isky tool room springs. I had the tool room springs prior, and they did hold up extremely well, and tested close to their original spring pressures after a couple hundred hours. That being said, myself, im not looking to try to get 300 plus hours out of valvesprings on an 800hp engine. Id rather simply replace them every few years, even if they only have 100 hours on them. Most 800 plus hp engines arent going 300 plus hours without being touched anyways. Springs are a disposable wear item.

As far as I know, there are only a handful of actual valvespring manufacturers. Most springs are relabeled . Comp cams owns crane cams. Id be willing to bet the springs are made under the same roof. The 928 spring, and the 99896 spring crane recommends for the 741, have a significant difference in pressures. Crane 99896 spring is 524lbs /in vs comp 928 at 354 lbs/in .

Spring setup is critical. Ive seen used heads with install heights all over the place. I had heads redone at a shop, and when i went and measured the install heights, I was shocked in how much variance there was. If i recall it was .050 to .100 variance among them. Of course they were not shimmed to make up the variance. So, what you end up with is different pressures all over the map. Not to mention they were setup a mile away from coil bind. The install, hardware, and overall fitment was way off. .050 doesnt sound like much, but can easily be 30lbs variance of seat pressure just from that alone.

One thing my new head guy does, is takes every spring out of the box, and puts it in the spring tester. Each one gets tested for seat pressure, open pressure, and coil bind, and records it. Heck, just brought him a set of merlin iron heads recently that were setup by another shop. No cups or locators, springs were set on top of a valve spring shim! The springs were eating the shims for lunch.

my point to all this, is spend the time setting up your springs. The best spring in the world isnt gonna save you if its installed improperly. In my case, the springs were digging into the locators, and eating away at the stem seals. The hardware needs to be a good fit. A locator with a .680 shoulder doesnt go with a spring that has a .740 inner spring ID.

It doesn’t look ideal for long term use. I’m hoping to get 500+ hours out of this one without so much as pulling a valve cover off. I’ll have a look at the Isky springs.

Tool room series springs from isky are around 500 a set right now. The crane spring, around 230 bucks, and 160 bucks for the comps.

Pac makes some high end endurance springs, manley nextek series, howards, lunati, all have some endurance style springs.

Imo, 500 hours is alot to ask out of a set of springs , unless its a low lift low rpm bbc. Like the 502, 454 mag engines that have under .500 lift stock and turn 5200rpm max. I doubt the valve job will go 500 hours anyways.

My head guy has only used Comp springs and cams (shelf or custom) for the 15+ yrs I have known him. There are some Comp springs he doesn't use and stays away from. I believe the 928's are one of them.

at one point, pac/peterson spring was supplying comp with their springs. Not sure if thats still the case. Psi makes isky springs i believe.

I hear ya on the setup. In my YouTube education they added a .05 shim and the seat pressure went from about 128 closer to 150#. That’s a pretty big deal.